Package-level declarations

Boolean<->String: format via toString; parse accepts exactly "true"/"false".

Byte<->Boolean: no canonical semantics in either direction.

Byte<->String: format via toString, strict decimal parse.

Double<->Boolean: no canonical semantics in either direction.

Double<->Byte: widens Byte -> Double exactly; refuses the lossy direction.

Double<->Float: widens Float -> Double exactly; refuses the lossy direction.

Double<->Int: widens Int -> Double exactly; refuses the lossy direction.

Double<->Long: no safe direction — both refuse with a guiding reason.

Double<->Short: widens Short -> Double exactly; refuses the lossy direction.

Double<->String: format via toString; parse via toDouble() (platform semantics — JVM accepts surrounding whitespace, f/d suffixes, and hex floats; the integer parses above are strict-decimal).

Duration<-> whole-milliseconds Long. Sub-millisecond precision truncates on the way out — the same trade-off as InstantLongConverter (millis are the de-facto wire unit).

Duration<-> ISO-8601 String ("PT1H30M"). Format via Duration.toIsoString, parse via Duration.parseIsoString — strict ISO only; Kotlin's lenient "1h 30m" form is rejected (wire formats want one canonical representation).

Float<->Boolean: no canonical semantics in either direction.

Float<->Byte: widens Byte -> Float exactly; refuses the lossy direction.

Float<->Int: no safe direction — both refuse with a guiding reason.

Float<->Long: no safe direction — both refuse with a guiding reason.

Float<->Short: widens Short -> Float exactly; refuses the lossy direction.

Float<->String: format via toString; parse via toFloat() (platform semantics — JVM accepts surrounding whitespace, f/d suffixes, and hex floats; the integer parses above are strict-decimal).

Instant<-> epoch-milliseconds Long. Sub-millisecond precision truncates on the way out.

Instant<-> ISO-8601 String: format via toString, parse via Instant.parse.

Int<->Boolean: no canonical semantics in either direction.

Int<->Byte: widens Byte -> Int; refuses the narrowing direction.

Int<->Short: widens Short -> Int; refuses the narrowing direction.

Int<->String: format via toString, strict decimal parse.

LocalDate<-> ISO-8601 String ("2026-06-12"). Parse throws on malformed input.

LocalDateTime<-> ISO-8601 String ("2026-06-12T09:30:00"). Parse throws on malformed input.

LocalTime<-> ISO-8601 String ("09:30:00"). Parse throws on malformed input.

Long<->Boolean: no canonical semantics in either direction.

Long<->Byte: widens Byte -> Long; refuses the narrowing direction.

Long<->Int: widens Int -> Long; refuses the narrowing direction.

Long<->Short: widens Short -> Long; refuses the narrowing direction.

Long<->String: format via toString, strict decimal parse.

Short<->Boolean: no canonical semantics in either direction.

Short<->Byte: widens Byte -> Short; refuses the narrowing direction.

Short<->String: format via toString, strict decimal parse.